This invention relates generally to electrical control systems and more particularly to an electrical system for disabling or interrupting electrical power applied to apparatus producing motion of an aerial work platform due to inadvertent or accidental actuation of a motion control device located on the upper control box.
Systems for preventing the unintentional operation of mechanical and electrical propulsion systems are generally known and take many forms. For example, a vehicle might contain selectively placed switches wherein the drive power to the traction means is interrupted when the operator leaves his operating station and thereafter prevents unintentional movement of the vehicle upon the return of the operator to the operating station without making a positive effort to properly reestablish conditions for operation. Also known are systems which automatically shut down motor operation whenever an adverse operating condition is detected. With respect to electrical equipment including household appliances, there are known systems which automatically interrupt power in the event that the apparatus is left unattended for a predetermined time to reduce the hazard associated therewith.
Accordingly, it is an object of the present invention to provide an improvement in electrical control apparatus which prevents undesired energization of motion producing apparatus.
It is another object of the invention to provide an electrical control circuit for enabling and automatically disabling the application of power to motion producing apparatus on an aerial work platform.
It is yet another object of the invention to inhibit the risk of accidents due to an operator or an obstruction or workpiece inadvertently contacting and operating a motion control device located on the upper control box of an aerial work platform while an operator is performing a predetermined task thereat.
Still a further object of the invention is to prevent inadvertent operation of an aerial work platform which would cause the platform or vehicle to move accidentally and which might thereby cause injury to the operator and/or personnel in the vicinity of the aerial work platform.